JSON To JSON Transformation | Template Engine for Java
You could try JOLT, advertised as a JSON to JSON transformation library written in Java.
Or you can search this thread for other libraries and tools which can transform JSON.
The new XSLT 3.0 draft also includes support for JSON as input and output format. Saxon has already started an implementation and seems to support for the JSON part.
You could try JSLT, which is a transform language where you write the fixed part of the output in JSON syntax, then insert expressions to compute the values you want to insert in the template. It's quite similar to how XSLT and XPath work together.
It's implemented in Java on top of Jackson.